19 votes
Accepted

For electricity use, which is better: Turning all appliances on at the same time, or spread out?

The "surge" that the electric utility was referring to is the demand charge: The kWh charge (consumption) is the measurement of the amount of energy the building uses over the given period ...
LShaver's user avatar
  • 11.9k
13 votes

What form of electrical lighting has the smallest energy-footprint?

i signed up just so i could make this comment. THelper♦ provided a good link to a DOE report on this topic, which i was researching because my roommate is skeptical about the advantages of efficient ...
giardia's user avatar
  • 231
13 votes

Are fuel cell electricity generators a sustainable way of making electricity?

No. There is no readily available supply of net-positive-energy hydrogen on Earth, where most human power usage takes place. Hydrogen fuel cells may be a useful component of a total energy system ...
Jean-Paul Calderone's user avatar
11 votes

Getting power from an innovative new mechanism

No, you cannot get more energy out than you put in. No, you cannot invent a perpetual motion machine.
410 gone's user avatar
  • 14.7k
10 votes
Accepted

Is electricity used at night more likely to be renewable?

In Ireland, electricity is equally likely to be from renewable sources during the day as during the night ENTSO-E, the European Network of Transmission System Operators for Electricity, provides a ...
LShaver's user avatar
  • 11.9k
8 votes
Accepted

Can 140 square miles of solar panels power the US?

Summary No, that's way too little. I think "140 miles square" has got mangled into "140 square miles". Running the numbers Following on from one of Elon Musk's presentations, which ...
410 gone's user avatar
  • 14.7k
8 votes
Accepted

How much energy would it cost to stabilize 2 tons of water at 70 degrees?

The stabilisation energy rate will be exactly exactly equal to the rate at which energy is lost. Assuming the tank is closed, so there are no evaporative losses, there are two other ways energy is ...
410 gone's user avatar
  • 14.7k
8 votes

How to ensure you are using efficient chargers for cell phones, laptop computers, and other electronic devices?

Power ratings -- choose level VI Take a look at any external power supply (EPS) you have lying around -- you should notice, along with all the regulatory markings, a roman numeral I through VI in a ...
LShaver's user avatar
  • 11.9k
7 votes

Electrical usage data logging with wireless data transfer

It sounds like the Kill A Watt wireless might be what you are after. For more alternatives keep reading. There is another product line called the Watts-Up that has USB connections to computers on ...
user2121874's user avatar
7 votes

How much energy do wall outlets with USB waste when not actively charging?

In most countries, legislation limits the amount of power a device on standby, i.e. under power but not performing a function, are allowed to use. In Europe it's 0.5 Watts (see EC Regulation No. 1275/...
Gannet's user avatar
  • 161
6 votes

Anything similar to GravityLight that can be readily purchased?

The big advantage of GravityLight is that you can pull the weight once and then you have electricity for a relatively long period (I read somewhere it's 30 minutes). This is ideal when you need to ...
THelper's user avatar
  • 14.5k
6 votes
Accepted

Does it make any difference to charge my electronic devices using an USB port?

To give a definite answer would require a lot of research and it would probably be quite impossible to give a "for sure" answer because there are some variables. Some computer power supplies are much ...
Maxfield Solar's user avatar
6 votes
Accepted

How much, if any, does resolution effect the net power consumption of watching online video?

The Natural Resources Defense Council commissioned a study in late 2015 to understand the energy consumption from 4K TVs, titled The Big Picture: Ultra High-Definition Televisions Could Add $1 Billion ...
LShaver's user avatar
  • 11.9k
6 votes

Is Tesla Powerwall a good investment?

No it is not. Your calculations of 13year ROI is based on the assumption that charging the power wall is free during the day time. It is not. Depending on your locale, either you need to factor in ...
Aron's user avatar
  • 380
6 votes

Any way for microinverter PV array to power a house when the grid is down?

tl;dr: Because of how the grid and your inverters work, it's unlikely that there is a solution for your current system. You will either need to set up a communication network with your microinverters ...
LShaver's user avatar
  • 11.9k
6 votes

For electricity use, which is better: Turning all appliances on at the same time, or spread out?

The primary issue being described is Peak Demand charge. The description in LShaver's answer explains a lot of that, but there are a few more pieces that I think are important: Why does peak demand ...
manassehkatz-Moving 2 Codidact's user avatar
5 votes

What's the average efficiency of pumped hydroelectric energy storage facilities?

In this question about rooftop hydro I covered the efficiency question almost as an aside. I can't find an actual plant with efficiency over 80%, only claims that that might be possible. The average ...
Móż's user avatar
  • 3,874
5 votes

Does it make any difference to charge my electronic devices using an USB port?

Computer PSUs generally only hit their rated efficiency when well loaded. Most desktop PCs have larger PSUs than they need, to allow for expansion, and so they are not fully loaded. Consequently it is ...
Flyto's user avatar
  • 3,690
5 votes

What is an easy way to cool off during the summer without electricity?

I developed a simple strategy suitable for living in a flat that is not on the top floor: When you wake up, close all windows and put the blindfolds down. This allows to prevent sun rays and hot air ...
Tomáš Zato's user avatar
5 votes

What is an easy way to cool off during the summer without electricity?

I am in Thailand now, it is the hottest time of year, relentless 40C and sun every day. No air conditioning. I survive by staying indoors during the hottest time of day, getting my clothes wet. ...
John Spence's user avatar
5 votes

Is leaving an electric oven on to heat bad for the oven?

Have to start by saying, a much better idea to heat with an electric than with a gas stove: as mentioned in this excellent question, gas stoves emit toxic carbon monoxide. Having said that, there are ...
anonymous2's user avatar
5 votes
Accepted

Temperature for hot water cylinder

Yes, higher thermostat temperatures mean more electricity consumption. Also your thermostat manual is right, bacteria growth is a valid concern. The ideal conditions for the Legionella bacteria to ...
THelper's user avatar
  • 14.5k
5 votes
Accepted

Does stocking my refrigerator with canned drinks (Cola) consume more energy?

No you shouldn't stop that. It's just thermal mass. The consumption of refrigerator is determined by two factors: How easily heat leaks inside the refrigerator through the insulated walls How often ...
juhist's user avatar
  • 4,954
4 votes

What is an easy way to cool off during the summer without electricity?

To keep body cool on hottest summer days, I use wet tee-shirt so as to mimic body's natural cooling system e.g. transpiration. Vaporisation of water really helps to feel good even under full sun. For ...
Rodolphe's user avatar
  • 141
4 votes

Do USB outlets waste energy just like conventional wall warts?

If you are looking for an efficient USB outlet, this post refers to a USB wall outlet that shuts off when not plugged in.
Vinod's user avatar
  • 191
4 votes
Accepted

Does the price of polysilicon (for solar PV panels) depend on oil prices?

I did some digging and found data with a bit more resolution. First, polysilicon prices since 2010: Source: Fu, et al, Economic Measurements of Polysilicon for the Photovoltaic Industry: Market ...
LShaver's user avatar
  • 11.9k
4 votes

Does the price of polysilicon (for solar PV panels) depend on oil prices?

No. As the graphs provided show, the prices both spike during the GFC, loosely speaking, but the oil price spikes later and declines faster, then continues a general slow rise while the price of ...
Móż's user avatar
  • 3,874
4 votes

Does the price of polysilicon (for solar PV panels) depend on oil prices?

Here's a quick answer; hopefully we'll see some more in depth answers too. Looking at the given charts closely, the price of polysilicon appears to decline from around $75 in early 2010 to $17 in ...
Highly Irregular's user avatar
4 votes

Does a PV panel take more energy to build than it generates in its lifetime?

Yes, PV is viable. That's why somewhere around a billion solar panels have been connected to the grid - about 200 GW of capacity, with another 50 GW or so coming online in 2016. I'm afraid that the ...
410 gone's user avatar
  • 14.7k

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